49 lines
1.7 KiB
Racket
49 lines
1.7 KiB
Racket
#lang racket
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;; (C) Copyright Collin Doering 2012
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;;
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;; This program is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;;
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;; This program is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;;
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;; You should have received a copy of the GNU General Public License
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;; along with this program. If not, see <http://www.gnu.org/licenses/>.
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;; File: post-fix-expressions.rkt
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;; Author: Collin J. Doering <rekahsoft@gmail.com>
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;; Date: Jul 8, 2012
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(define (parse-expr-list xs)
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(cond [(empty? xs) (printf "~n")]
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[else (printf "~a~n" (eval-expr (string->list (first xs))))
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(parse-expr-list (rest xs))]))
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(define (eval-expr xs)
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(define (eval-expr-H xs ys)
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(cond [(and (empty? xs) (empty? ys)) (error 'invalid-expr)]
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[(and (empty? xs) (equal (length ys) 1)) (first ys)]
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[(number? (first xs)) (eval-expr-H (rest xs) (cons (char->integer (first xs)) ys))]
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[(char? )])))
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(define str-tb-eval(make-parameter '()))
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(define runtime-options
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(command-line
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#:program "Postfix expression evaluator"
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#:once-any
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[("-s" "--string") str "Pass in one or more strings to be evaluated"
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(str-tb-eval (cons (str-tb-eval)))]))
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(parse-command-line "postfix-exprs" (current-command-line-arguments) runtime-options)
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(if (empty? (str-tb-eval))
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(parse-expr-list (str-tb-eval))
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(eval-expr-interactive))
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